SUPPLEMENTAL INDENTURE

SUPPLEMENTAL INDENTURE NO. 10

FROM

OKLAHOMA GAS AND ELECTRIC

COMPANY

TO

UMB BANK, N.A.

TRUSTEE

______________

DATED AS OF DECEMBER   1, 2008

___________________________

SUPPLEMENTAL TO INDENTURE

DATED AS OF OCTOBER   1, 1995

TABLE OF CONTENTS

Page

ARTICLE ONE

RELATION TO INDENTURE; DEFINITIONS

ARTICLE TWO

8.25% SENIOR NOTES, SERIES DUE JANUARY   15, 2019

ARTICLE THREE

MISCELLANEOUS

Exhibit A – Form of 8.25% Senior Notes, Series due January 15, 2019

SUPPLEMENTAL INDENTURE No. 10, made as of the 1st day of December, 2008 by and between OKLAHOMA GAS AND ELECTRIC COMPANY, a corporation duly organized and existing under the laws of the State of Oklahoma (the “Company”), and UMB BANK, N.A., a national banking association duly organized and existing under the laws of the United States, as trustee (the “Trustee”):

WITNESSETH:

WHEREAS, the Company has heretofore executed and delivered its Indenture (hereinafter referred to as the “Indenture”), made as of October 1, 1995; and

WHEREAS, the Company has heretofore executed and delivered its Supplemental Indenture No. 1 dated as of October 16, 1995, adding to the covenants, conditions and agreements of the Indenture certain additional covenants, conditions and agreements to be observed by the Company, and creating two series of Notes designated “7.30% Senior Notes, Series due October 15, 2025” and “6.250% Senior Notes, Series due October 15, 2000”; and

WHEREAS, the Company has heretofore executed and delivered its Supplemental Indenture No. 2 dated as of July 1, 1997, adding to the covenants, conditions and agreements of the Indenture certain additional covenants, conditions and agreements to be observed by the Company, and creating two series of Notes designated “6.65% Senior Notes, Series due October 15, 2027” and “6.50% Senior Notes, Series due July 15, 2017”; and

WHEREAS, the Company has heretofore executed and delivered its Supplemental Indenture No. 3 dated as of April 1, 1998, adding to the covenants, conditions and agreements of the Indenture certain additional covenants, conditions and agreements to be observed by the Company, and creating a series of Notes designated “6½% Senior Notes, Series due April 15, 2028”; and

WHEREAS, the Company has heretofore executed and delivered its Supplemental Indenture No. 4 dated as of October 15, 2000, adding to the covenants, conditions and agreements of the Indenture certain additional covenants, conditions and agreements to be observed by the Company, and creating a series of Notes designated “7.125% Senior Notes, Series due October 15, 2005”; and

WHEREAS, the Company, the Trustee and The Bank of New York (the “Prior Trustee”) have heretofore executed and delivered Supplemental Indenture No. 5 dated as of October 24, 2001, providing for the resignation of the Prior Trustee and the acceptance, by the Trustee, of its appointment as trustee and the assumption of all duties and responsibilities of the trustee under the Indenture; and

WHEREAS, the Company has heretofore executed and delivered its Supplemental Indenture No. 6 dated as of August 1, 2004, adding to the covenants, conditions and agreements of the Indenture certain additional covenants, conditions and agreements to be observed by the Company, and creating a series of Notes designated “6.50% Senior Notes, Series due August 1, 2034”; and

WHEREAS, the Company has heretofore executed and delivered its Supplemental Indenture No. 7 dated as of January 1, 2006, adding to the covenants, conditions and agreements of the Indenture certain additional covenants, conditions and agreements to be observed by the Company, and creating two series of Notes designated “5.15% Senior Notes, Series due January 15, 2016” and “5.75% Senior Notes, Series due January 15, 2036”; and

WHEREAS, the Company has heretofore executed and delivered its Supplemental Indenture No. 8 dated as of January 15, 2008, adding to the covenants, conditions and agreements of the Indenture certain additional covenants, conditions and agreements to be observed by the Company, and creating a series of Notes designated “6.45% Senior Notes, Series due February 1, 2038”; and

WHEREAS, the Company has heretofore executed and delivered its Supplemental Indenture No. 9 dated as of September 1, 2008, adding to the covenants, conditions and agreements of the Indenture certain additional covenants, conditions and agreements to be observed by the Company, and creating a series of Notes designated “6.350% Senior Notes, Series due September 1, 2018”; and

WHEREAS, Section 2.05 of the Indenture provides that Notes shall be issued in series and that a Company Order shall specify the terms of each series; and

WHEREAS, Boatmen’s First National Bank of Oklahoma was formerly the Trustee under the Indenture and NationsBank, N.A. succeeded Boatmen’s First National Bank of Oklahoma as Trustee pursuant to Section 9.13 of the Indenture, The Bank of New York subsequently succeeded Boatmen’s First National Bank of Oklahoma as Trustee pursuant to Section 9.13 of the Indenture and UMB Bank, N.A., has subsequently succeeded The Bank of New York as Trustee pursuant to Section 9.11 of the Indenture; and

WHEREAS, the Company has this day delivered a Company Order setting forth the terms of a series of Notes designated “8.25% Senior Notes, Series due January 15, 2019” (hereinafter sometimes referred to as the “Senior Notes due 2019”); and

WHEREAS, Section 13.01 of the Indenture provides that the Company and the Trustee may enter into indentures supplemental thereto for the purposes, among others, of establishing the form of Notes or establishing or reflecting any terms of any Note and adding to the covenants of the Company; and

WHEREAS, the execution and delivery of this Supplemental Indenture No. 10 (herein, “this Supplemental Indenture”) have been duly authorized by a resolution adopted by the Board of Directors of the Company;

NOW, THEREFORE, THIS INDENTURE WITNESSETH:

That in order to set forth the terms and conditions upon which the Senior Notes due 2019 are, and are to be, authenticated, issued and delivered, and in consideration of the premises of the purchase and acceptance of the Senior Notes due 2019 by the Holders thereof and the sum of one dollar duly paid to it by the Trustee at the execution of this Supplemental Indenture, the receipt whereof is hereby acknowledged, the Company covenants and agrees with the Trustee for the

equal and proportionate benefit of the respective Holders from time to time of the Senior Notes due 2019, as follows:

ARTICLE ONE

RELATION TO INDENTURE; DEFINITIONS

(a)       Capitalized terms used herein without definition shall have the meanings specified in the Indenture;

(b)       All references herein to Articles and Sections, unless otherwise specified, refer to the corresponding Articles and Sections of this Supplemental Indenture; and

(c)       The terms “hereof,” “herein,” “hereby,” “hereto,” “hereunder” and “herewith” refer to this Supplemental Indenture.

ARTICLE TWO

8.25% SENIOR NOTES, SERIES DUE JANUARY 15, 2019

Section 2.01    There shall be a series of Notes designated the “8.25% Senior Notes, Series due January 15, 2019” (the “Senior Notes due 2019”). The Senior Notes due 2019 shall be limited to $250,000,000 aggregate principal amount except as provided in Section 2.08 hereof.

Section 2.02    Except as otherwise provided in Section 2.05 hereof, the principal amount of the Senior Notes due 2019 shall be payable on the stated maturity date of January 15, 2019.

Section 2.03    The Senior Notes due 2019 shall be dated their date of authentication as provided in the Indenture and shall bear interest from their date at the rate of 8.25% per annum, payable semiannually on January 15 and July 15 of each year, commencing July 15, 2009. The Regular Record Dates with respect to such January 15 and July 15 interest payment dates shall be January 1 and July 1, respectively. Principal and interest shall be payable to the persons and in the manner provided in Sections 2.04 and 2.12 of the Indenture.

Section 2.04    The Senior Notes due 2019 shall be payable at the corporate trust office of the Trustee and at the offices of such paying agents as the Company may appoint by Company Order in the future.

Section 2.05    The Company, at its option, may redeem on any date all or, from time to time, any part of the Senior Notes due 2019, upon notice as provided in the Indenture, at a redemption price equal to the greater of (i) 100% of the principal amount of such Senior Notes due 2019 to be redeemed and (ii) the sum of the present values of the remaining scheduled payments of principal and interest thereon (not including any portion of such payments of interest accrued to the date of redemption) discounted to the date of redemption on a semiannual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate plus 50 basis points, plus in each case accrued and unpaid interest thereon to the date of redemption.

“Treasury Rate” means, with respect to any redemption date (i) the yield, under the heading which represents the average for the immediately preceding week, appearing in the most recently published statistical release designated “H.15(519)” or any successor publication which is published weekly by the Board of Governors of the Federal Reserve System and which establishes yields on actively traded U.S. Treasury securities adjusted to constant maturity under the caption “Treasury Constant Maturities,” for the maturity corresponding to the Comparable Treasury Issue (if no maturity is within three months before or after the Remaining Life (as defined below), yields for the two published maturities most closely corresponding to the Comparable Treasury Issue will be determined and the Treasury Rate will be interpolated or extrapolated from such yields on a straight line basis, rounding to the nearest month) or (ii) if such release (or any successor release) is not published during the week preceding the calculation date or does not contain such yields, the rate per annum equal to the semiannual equivalent yield to maturity of the Comparable Treasury Issue, calculated using a price for the Comparable Treasury Issue (expressed as a percentage of its principal amount) equal to the Comparable Treasury Price for such redemption date. The Treasury Rate will be calculated on the third business day preceding the date fixed for redemption.

“Comparable Treasury Issue” means the U.S. Treasury security selected by an Independent Investment Banker as having a maturity comparable to the remaining term (“Remaining Life”) of the Senior Notes due 2019 to be redeemed that would be utilized, at the time of selection and in accordance with customary financial practice, in pricing new issues of corporate debt securities of comparable maturity to the remaining term of such Senior Notes due 2019.

“Comparable Treasury Price” means (1) the average of five Reference Treasury Dealer Quotations for such redemption date, after excluding the highest and lowest Reference Treasury Dealer Quotations, or (2) if the Independent Investment Banker obtains fewer than four such Reference Treasury Dealer Quotations, the average of all such quotations.

“Independent Investment Banker” means either Mizuho Securities USA Inc., Greenwich Capital Markets, Inc., UBS Securities LLC or another independent investment banking institution of national standing appointed by the Company.

“Reference Treasury Dealer” means (1) each of Greenwich Capital Markets, Inc., Mizuho Securities USA Inc. and UBS Securities LLC or their respective successors, and any other primary U.S. government securities dealer in the United States (a “Primary Treasury Dealer”) selected by Greenwich Capital Markets, Inc., Mizuho Securities USA Inc. or UBS Securities LLC or their respective successors, provided, however, that if any of the foregoing ceases to be a Primary Treasury Dealer, the Company will substitute therefor another Primary Treasury Dealer and (2) any other Primary Treasury Dealer selected by the Company after consultation with the Independent Investment Banker.

“Reference Treasury Dealer Quotations” means, with respect to each Reference Treasury Dealer and any redemption date, the average, as determined by the Independent Investment Banker, of the bid and asked prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount) quoted in writing to the Independent Investment Banker at 5:00 p.m., New York City time, on the third business day preceding such redemption date.

The Senior Notes due 2019 shall not be subject to any sinking fund.

Section 2.06    The Senior Notes due 2019 shall be issued in fully registered form without coupons in a minimum denomination of $2,000 and multiples of $1,000 in excess thereof.

Section 2.07    The Release Date (as defined in the Indenture) occurred on April 6, 1998. Accordingly, the Senior Notes due 2019 shall be issued as unsecured general obligations of the Company. The Senior Notes due 2019, and all other Notes issued or to be issued under the Indenture, will not be secured by First Mortgage Bonds of the Company and will not be entitled to the lien of or the benefits provided by the First Mortgage, which has been extinguished.

Section 2.08    The Senior Notes due 2019 may be reopened and additional notes of the Senior Notes due 2019 may be issued in excess of the limitation set forth in Section 2.01, provided that such additional notes will contain the same terms (including the maturity date and interest payment terms) as the othe